IV

Unthrifty loveliness, why dost thou spend Upon thyself thy beauty’s legacy? Nature’s bequest gives nothing, but doth lend, And being frank she lends to those are free: Then, beauteous niggard, why dost thou abuse The bounteous largess given thee to give? Profitless usurer, why dost thou use So great a sum of sums, yet canst not live? For having traffic with thyself alone, Thou of thyself thy sweet self dost deceive: Then how when nature calls thee to be gone, What acceptable audit canst thou leave? Thy unused beauty must be tombed with thee, Which, used, lives th’ executor to be.

Sonnet 4 is a critique of the vanity and self-indulgence that can come with physical beauty. The speaker accuses the subject of the sonnet, an unnamed young man, of wasting his good looks on himself rather than using them to propagate the species through procreation. Shakespeare argues that beauty is not something to be hoarded or used selfishly, but rather a gift from nature that must be shared in order to have any real value. He admonishes the young man for being a "profitless usurer," one who uses his beauty for his own pleasure but cannot pass it on to future generations. The sonnet concludes with the warning that the young man's beauty, if left unused, will die with him, whereas if he shares it through reproduction, it will live on in his offspring. Shakespeare suggests that beauty, like all gifts from nature, must be used wisely and with an eye to the future, if it is to have any lasting significance.